| 摘要 |
PURPOSE:To compact a filter capable of reducing the generation of higher harmonics and fixing the contents of each higher harmonic. CONSTITUTION:An inverter 2 having serial triple structure is connected to a system 1 through a reactor L1, the reactive power QL of a load and the reactive power Qi of the inverter 2 are detected and a deviation between both the reactive power signals QL, Qi is amplified by an amplifier 6. The amplifier result is converted into frequency by a voltage control oscillator 7, the frequency is divided by a counter 8 and a gate generating circuit 9 controls the inverter 2 at conduction width 120 deg.. If the reactive power QL is increased when the load has a delay phase, the frequency of the oscillator 7 is reduced, the inverter 2 is controlled by the delay phase, active power is allowed to flow from the system 1 into the inverter 2, DC voltage Ed and output voltage are changed, and the reactive power is controlled at Qi=QL. Since the inverter 2 is controlled by the conduction width 120 deg., the 3rd higher harmonic is not generated and the contents of higher harmonic in each order is fixed. |
